Car companies have recalled about 11 million vehicles in the U.S. so far this year. General Motors Co. has called back the most: 6 million, including more than 2 million for an ignition switch issue linked to 13 deaths.

That's already half the 22 million cars recalled in all of 2013, according to the National Highway Traffic Safety Administration, and more than a third of the recent high of 30.8 million vehicles in 2004.

Other big recalls this year include 650,000 Jeep Grand Cherokees and Dodge Durangos, 1 million cars from Nissan — including its popular Altima and Sentra sedans — almost 900,000 Honda Odyssey minivans and about 700,000 Toyota Prius hybrids.

Ford on Monday recalled more than 400,000 older cars and sport utility vehicles to fix rusting frame parts or faulty seats, depending on the model.

Also Monday, GM began shipping parts to its dealers to repair ignition switches on the cars already recalled. But there's such a shortage of parts and backlog of cars to be repaired that it may take until nearly the end of the year to fix all the autos, GM said.

Analysts say consumers shouldn't be alarmed by the high recall rate.

"This is the new normal for recall numbers," said Karl Brauer, an analyst at auto information company Kelley Blue Book.

Automakers are more willing to do recalls today than they were five years ago because they fear incurring the wrath of federal regulators after seeing how delayed recalls caused big problems for Toyota Motor Corp., Brauer said.

This year, Toyota agreed to pay a $1.2-billion fine to settle a four-year federal criminal investigation into whether it properly told regulators about safety complaints concerning sudden acceleration of its vehicles. It also has paid NHTSA about $66 million in fines in recent years for not promptly recalling vehicles.

"Toyota changed the thinking on recalls," Brauer said. "The cost of a recall is a drop in the bucket compared to the cost of what happens if you don't do it."

Although every car company has had periodic recalls, some call back far fewer cars than others, according to analyses by auto shopping information company ISeeCars.

From 2005 into March of this year, Mercedes-Benz has the best recall rate, calling back only 38 vehicles for every 100 sold. Rounding out the top five, Mazda by the same measure scored 55; Kia, 68; BMW, 87; and Nissan, 90.

Nissan had the best recall timeliness: 86.5% of its recall campaigns occurred within the first three years of a car being sold. Other companies with good timeliness records were Chrysler, 84.4%; Mitsubishi, 84.4%; Volvo, 83.7%; and BMW, 80.7%. GM, which faces several federal investigations into whether it delayed recalls of the cars with the faulty ignition switch, is in the middle of the pack, ranking eighth among the 15 automakers in the ISeeCars analysis.

Both recall rate and timeliness are important metrics, said Phong Ly, chief executive of ISeeCars.

The recall rate provides a long-term picture of how often a manufacturer produces a vehicle with a defect. The timeliness factor is an indication of how willing an automaker is to own up to a problem and initiate a recall.

Toyota, for example, had the top recall rate from 1995 to 2004, but a rash of problems in recent years dropped it to 15th, the worst ranking for the latest period in the study. It also came in last in the most recent period for recall timeliness with just 56.5% of its recalls coming within three years of a car's sale.

But Toyota does appear to be working to improve its numbers from the last 10 years, Ly said, including "launching a 'rapid response team' to address customer issues and lengthening the new vehicle development timeline by four weeks."

As recalls mount, drivers should be careful to get their vehicles fixed, warned AAA.

"Contact your local dealer and have the repair completed as soon as possible," said Steve Mazor, manager of the Automobile Club of Southern California's Automotive Research Center, "and remember to ask if you're entitled to a rental car while the repairs are conducted."

Car owners also need to be mindful of actions taken by manufacturers that technically aren't recalls. These are called technical service bulletins: recommended repairs to correct specific vehicle problems if consumers complain about them.

Owners should ask about such service campaigns when they take their vehicles in for periodic maintenance, Mazor said.

NHTSA also has urged car owners to check whether their vehicles have been recalled and, if so, get them fixed. That's especially important for people who have bought used cars. The recall notice might have been sent to the previous owner, leaving the current owner in the dark.

The agency is developing an online service that will enable owners or buyers of used cars to type in the vehicle's identification number and learn whether the car has been recalled. Some car companies already offer a similar research tool on their websites.

GM said it is culling registration data to get the addresses of owners of the cars it has recalled.

Car vehicle history report company Carfax estimates that 3.5 million vehicles with an unfixed recall were listed for sale last year.

A study by the Society of Automotive Engineers that looked at recalls in 2008 found that the older a car was, the less likely it was to be repaired. The trade group found that only 42% of the 2000 model year vehicles recalled in 2008 were repaired. That jumped to 79% for 2008 model year vehicles.

One reason is that new cars are more likely to be serviced by dealers who check whether there are outstanding recalls for vehicles in their service bays and make the repairs.

For just a few million dollars, General Motors Co. could have replaced a defective ignition switch that ultimately has been linked to 13 deaths and is expected to cost the automaker billions in repairs, fines and litigation.

Ford’s revolutionary aluminum-body F-150 pickup truck does well in most crash tests but is significantly more expensive to repair, according to an analysis by the Insurance Institute for Highway Safety.

Automakers say they are building the best cars ever, and there’s proof on the road. The average age of vehicles in the U.S. has climbed to a record 11.5 years, according to research firm IHS Automotive.